fix zsh completion output (#1014)

cmd/root.go

@@ -409,7 +409,7 @@ Zsh:
 	$ echo "autoload -U compinit; compinit" >> ~/.zshrc
 
 	# To load completions for each session, execute once:
-	$ k3d completion zsh > "${fpath[1]}/k3d"
+	$ k3d completion zsh > "${fpath[1]}/_k3d"
 
 	# You will need to start a new shell for this setup to take effect.
 

docs/usage/commands/k3d_completion.md

@@ -8,41 +8,40 @@ To load completions:
 
 Bash:
 
-	$ source <(k3d completion bash)
+ $ source <(k3d completion bash)
 
-	# To load completions for each session, execute once:
+ # To load completions for each session, execute once:
-	# Linux:
+ # Linux:
-	$ k3d completion bash > /etc/bash_completion.d/k3d
+ $ k3d completion bash > /etc/bash_completion.d/k3d
-	# macOS:
+ # macOS:
-	$ k3d completion bash > /usr/local/etc/bash_completion.d/k3d
+ $ k3d completion bash > /usr/local/etc/bash_completion.d/k3d
 
 Zsh:
 
-	# If shell completion is not already enabled in your environment,
+ # If shell completion is not already enabled in your environment,
-	# you will need to enable it.  You can execute the following once:
+ # you will need to enable it.  You can execute the following once:
 
-	$ echo "autoload -U compinit; compinit" >> ~/.zshrc
+ $ echo "autoload -U compinit; compinit" >> ~/.zshrc
 
-	# To load completions for each session, execute once:
+ # To load completions for each session, execute once:
-	$ k3d completion zsh > "${fpath[1]}/k3d"
+ $ k3d completion zsh > "${fpath[1]}/_k3d"
 
-	# You will need to start a new shell for this setup to take effect.
+ # You will need to start a new shell for this setup to take effect.
 
 fish:
 
-	$ k3d completion fish | source
+ $ k3d completion fish | source
 
-	# To load completions for each session, execute once:
+ # To load completions for each session, execute once:
-	$ k3d completion fish > ~/.config/fish/completions/k3d.fish
+ $ k3d completion fish > ~/.config/fish/completions/k3d.fish
 
 PowerShell:
 
-	PS> k3d completion powershell | Out-String | Invoke-Expression
+ PS> k3d completion powershell | Out-String | Invoke-Expression
-
-	# To load completions for every new session, run:
-	PS> k3d completion powershell > k3d.ps1
-	# and source this file from your PowerShell profile.
 
+ # To load completions for every new session, run:
+ PS> k3d completion powershell > k3d.ps1
+ # and source this file from your PowerShell profile.
 
 ```
 k3d completion SHELL
@@ -64,5 +63,4 @@ k3d completion SHELL
 
 ### SEE ALSO
 
-* [k3d](k3d.md)	 - https://k3d.io/ -> Run k3s in Docker!
+* [k3d](k3d.md)  - <https://k3d.io/> -> Run k3s in Docker!
-